双江口水电站坝体材料及覆盖层坝基动力变形特性研究

Study on Dynamic Deformation Characteristics of Dam Materials and Overburden in Shuangjiangkou Hydropower Station

筑坝材料的动力变形特性是进行大坝动力反应分析的基本依据之一,采用等效粘弹性模型计算时主要包括最大动剪模量Gmax与平均有效主应力的关系,动剪模量比G/Gmax与动剪应变幅γd的关系以及阻尼比λ与动剪应变幅γd的关系等。这些关系反映了在动荷载作用下土的应力应变关系的非线性与粘滞性特征。双江口水电站坝体材料及覆盖层坝基动力特性试验由两种试验方法同时进行,本文通过对比综合两种方法的试验参数。结果表明两种方法在不同的动应变区间有差异,应根据不同的计算模型选择使用。

The dynamic deformation characteristics of dam materials is one of the bases of analyzing the dynamic response of the dam.The calculation with equivalent viscoelastic model includes the relationships between the maximum dynamic shear modulus Gmax and average effective principal stress,between the dynamic shear modulus ratio G/Gmax and dynamic shear strain amplitude γd,between the damping ratio λ and dynamic shear strain amplitude γd and so on.These relationships reflect the nonlinear and viscous characteristics of stress-strain relationship of the soil under dynamic loading.The tests of dynamic deformation characteristics of the dam materials of Shuangjiangkou Hydropower Station are conducted by using two test methods at the same time.The parameters of the two test methods are compared here,the results show that the dynamic strain area is different in these two methods,which should be chosen based on different calculation models.